Remote-controlled vehicles, particularly Unmanned Air Vehicles (UAVs), have been in use for years for many different applications. At a simple end, hobbyists steer remote-controlled cars or boats or fly remote-controlled airplanes for entertainment. At a sophisticated end, military and intelligence agencies fly UAVs to conduct surveillance in hostile territories. UAVs are equipped with cameras, microphones, and other sensors to gather intelligence. These sophisticated, complex UAVs are controlled from remote stations.
Control of such devices can be a complex problem. Even high-end hobbyist UAVs have control panels that cannot be practically hand held because of the many levers, dials, switches, and other control devices the operator uses to direct such a device. Moreover, transmitting the control information from the many control devices, receiving and decoding the instructions at the remote device, and executing the instructions represent involved data communication problems.
In addition, a limitation particularly limiting UAVs is that, like manned aircraft, a UAV has to have the capacity to carry enough fuel or power to complete its mission. The longer the mission, the more fuel or power that must be carried, and, the larger the UAV must be to carry its own source of power. Furthermore, hovering tends to consume substantially more power than forward flight. Thus, UAVs commonly use fixed-wing, forward flight designs.
For example, the Pointer by AeroVironment is a fixed-wing UAV. The Pointer has a length of 6 feet with a wingspan of 9 feet. The Pointer weighs 8 pounds with a payload of 2 pounds and a battery weighing 2.2 pounds. It is hand-launched by being thrown into the air. The Pointer has a flight duration of 1.5 hours with a range of 5 miles.
However, forward-flight is not an optimal flight mode for all purposes. For example, forward-flight is not an optimal flight mode for surveillance. A forward-flying platform moves over and may move past targets of interest. While a forward-flying platform can circle a target of interest, gathering information about the target may be complicated by moving a camera lens or other directional sensor to focus on the target. As a result, a hovering platform presents a more desirable point from which to observe a target of interest. Forward-flight also is not optimal for a platform to be used for relaying or redirecting signals. For these purposes it would be advantageous to have a hovering platform suspended over a stationary ground point to redirect and relay signals for which a line-of-sight transmission is desirable but not possible. Such a hovering platform would enable communications or other electromagnetic transmission to be broadcast over buildings or other barriers that ordinarily would block such transmissions.
Hovering vehicles generally consume more power than forward-flying vehicles. To try to develop a more efficient hovering vehicle, micro air vehicles (MAVs) have been created using flapping wing technologies to create lift. The existence of insects and small flying animals suggests that flapping wing technologies can be an efficient way to create lift. For one example, a collaboration between Caltech and UCLA has developed an MAV called the MicroBat. The MicroBat recently broke the world record in flapping wing flight of an MAV with a flight lasting only 6 minutes and 17 seconds. The MicroBat carries a polymer lithium ion battery as its power source and carries a radio transceiver. The total weight of the MicroBat is only 12 grams. However, in flapping wing flight, aerodynamic flow properties are complex and difficult to manage. Thus, just as land-based vehicles tend not to be based on walking movements of bipeds or quadrupeds but on simpler-to-manage rotating motivators such as wheels, it would be simpler to effect hovering using a rotary wing design such as a helicopter. Unfortunately, an efficient way to sustain hovering flight for very long intervals has proven elusive.
Thus, there is an unmet need in the art for facilitating sustained, hovering flight and thereby allowing for simpler and more efficient ways to perform aerial surveillance of a target of interest or to redirect and relay electromagnetic signals from a transmission site to a receiver or other target.